Troubleshooting No Power To Trailer Brakes with Redarc Tow-Pro Brake Controller

Updated 07/24/2025 | Published 12/08/2023

Products Featured in This Question

Redarc Tow-Pro Liberty Brake Controller w/ Universal Wiring Harness - Dash Knob - Proportional

(3064)

$217.00

Redarc Tow-Pro Elite Brake Controller - Dash Knob - Off-Road Mode - Up to 3 Axles - Proportional

(1727)

$290.00

Question:

Oiye oiye..I just lost trailer brakes on caravan. I have a redarc dial in dash. No lights on dial now when sitting idle. If i hold it in it slowly glows green on and off. So it has power to it. Any ideas? Fuse for trailer is fine under hood. Usually glows yellowish colour while driving then gets red or orange when I press brakes. I know i can recallibrate but button..nreds to be driven as part of process too..Online chat reckons its not recognising a trailer plugged in..might have to check plug wires..but I just did that yesterday cause fridge wont run on 12v either. I have checked multimeter and I have 12v power behind fridge. Any ideas? Cheers

asked by: Shem B

Expert Reply:

The best way to test your Redarc Tow-Pro Elite # RED44FR or Liberty # RED52VR brake controller is by cutting the blue wire coming out of it about 6" away from the controller and using a circuit tester to make sure power is coming out of the controller and going towards your trailer brakes. Try using your manual override by pushing the button to send power on that blue wire and you can verify this function.

If you do get power coming out of the controller then you have an issue with the wiring somewhere between where you cut the blue wire and your brakes, but if you don't get power coming out of that blue wire then there is something going on with the controller and you might need to take advantage of the 2-Year Warranty (if that still applies).

When checking your wiring you want to look for any places where the wires are cut, pinched, or damaged and replace as necessary. Be sure to check all of your connections as well, including the connections inside your trailer and tow vehicle 7-Way connectors.

expert reply by: Jon G

Martyj

4/28/2024

Hi John, you say test the blue wire for power how much power should I get with my circuit test 12/13 volts or less, I am getting 1.98 volts Regards Marty

Jon G.

4/29/2024

@Martyj Are you using the manual override and increasing the output of the controller? You should be getting 12V/13V with the manual override.

Dale W.

7/24/2025

Just installed but only getting intermittent blue light. No power to rear 7 way. Any tips?

Jon G.

7/24/2025

@DaleW Is the light "breathing" when you press the manual override? If that's the case then you need to check the trailer plug and the blue output wire from the controller. If the LED is flashing a blue color then we're n at issues with the power supply to the controller or possible damage to the remote head cable. I'd recheck that your wiring is correct and in good shape. Let me know what you find out!